Enter your input voltage and the two resistor values. FigureDesk computes the output voltage at the node between them, the current through the divider, and the power each resistor dissipates.
Your numbers
Connected between Vin and the output node.
Connected between the output node and ground.
Result
Output voltage (Vout)
6 V
Given Vin = 9 V, R1 = 1000 Ω, R2 = 2000 Ω → Vout = Vin × R2 / (R1 + R2) = 6 V, I = Vin / (R1 + R2) = 0.003 A
Two resistors in series across a voltage source split that voltage in proportion to their resistance. The output is taken from the node between R1 (connected to the input) and R2 (connected to ground) — the same current flows through both, so their voltage drops divide the input voltage according to the ratio R2 / (R1 + R2).
Vout = Vin × R2 / (R1 + R2)
I = Vin / (R1 + R2)
A 9 V supply with R1 = 1,000 Ω and R2 = 2,000 Ω:
Common uses include scaling a higher voltage down to a level a sensor or ADC input can read safely, setting a reference or bias voltage, and reading a variable resistance (like a potentiometer or sensor) as a voltage.
This calculator assumes nothing draws current from the output node. In reality, any load you connect there acts as a resistor in parallel with R2, lowering the effective resistance below R2 and pulling the real output voltage below this result — the effect is larger the closer the load's resistance is to R2.
Pick a ratio R2 / (R1 + R2) that gives the output voltage you want, then scale both resistors up or down together to control current draw — smaller resistors draw more current and are less affected by a downstream load, but dissipate more power and draw more from the source.
Every resistor has a maximum power rating (commonly 1/8 W, 1/4 W, 1/2 W...). If the computed power in R1 or R2 exceeds the resistor's rating, it will overheat — choose a higher-wattage resistor or increase both resistances to reduce current.
The underlying relationship this calculator applies — solve for any of voltage, current, resistance, or power.
Read a physical resistor's color bands to confirm its value before using it in a divider.
A different single-resistor circuit — size a current-limiting resistor for an LED instead.
FigureDesk results are advisory and do not replace a licensed electrician, a qualified engineer, or the applicable local electrical code. Verify any electrical work against your local code and with a qualified professional before relying on it.